1 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4544.
| 2 Present address is the Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0126.
| 3 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4544.
| 4 Department of Comparative Medicine, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4544.
| 5 Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4544.